Stabilization of halogenated solvents

ABSTRACT

CHLORINATED OR BROMINATED ALKENES CONTAINING 2-4 CARBON ATOMS STABILIZED WITH TRIMETHYL ORTHOFORMATE AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF C1-C4 ALKANOLS, C1-C4 ALKYL CYANIDES, 1,4-DIOXANE, TRIOXANE AND C1-C4 NITROALKANES.

United States Patent Oflice 3,564,061 Patented Feb. 16, 1971 Int. Cl. (107e 17/40, 17/42 US. Cl. 260-6525 Claims ABSTRACT OF THE DISCLOSURE Chlorinated or brominated alkenes containing 2-4 carbon atoms stabilized with trimethyl orthoformate and a compound selected from the group consisting of C C alkanols, C -C alkyl cyanides, 1,4-dioxane, trioxane and C -C nitroalkanes.

This invention relates to the stabilization of halogenated saturated aliphatic hydrocarbons.

It is well known that saturated aliphatic hydrocarbons containing halogenated groups, such as chlorine, are unstable when contacted with metal such as aluminum or its alloys, magnesium and its alloys, amongst others. The instability results in decomposition of the halogenated hydrocarbon with the concurrent formation of halogenated hydracids and discoloration of the halogenated hydrocarbon. This introduces serious disadvantages in the use of such halogenated hydrocarbons in such applications as degreasing solvents and/or cleaning solvents for metallic parts or elements.

It is an object of this invention to overcome the above mentioned deficiencies while achieving effective stabilization of the halogenated aliphatic hydrocarbons and thereby enabling use thereof in degreasing and/ or cleaning of metal parts, plastics, textiles and other materials, without observing degradation of the solvent or degradation or discoloration of the materials treated.

In accordance with the practice of this invention, the desired stabilization of the halogenated aliphatic hydrocarbons is achieved by the combination with the halogenated hydrocarbon to include one or more ortho-esters having the formula in which R is a group selected from the group consisting of hydrogen or an alkyl group containing 1 to 3 carbon atoms and R R and R are groups selected from the group consisting of an alkyl group containing 1 to 3 carbon atoms such as methyl, ethyl and propyl groups with or without substituent groups thereon. These R, R R and R groups may be the same or they may differ one from another in the compound. By way of example, the following ortho-ester compounds are suitable for the stabilization of halogenated aliphatic hydrocarbons in accordance with the practice of this invention, namely: triethylorthoformate, trimethylorthoacetate, ethyldimethylorthoacetate and preferably trimethylorthoformate.

In order to achieve the desired stabilization, the orthoester is incorporated in the halogenated hydrocarbon in an amount within the range of 0.001 to 15% by weight and preferably 1 to 5% by weight based upon the halogenated hydrocarbon.

Other organic compounds can advantageously be employed in synergistic combination with the ortho-esters in the stabilization of the halogenated hydrocarbons in accordance with a further feature of this invention. The stabilization eifect of the ortho-esters and the stabilization of the halogenated hydrocarbons by means of the combination of stabilizers of this invention has been found to be particularly advantageous by reason of the fact that the stabilizing action of the combination is markedly greater than the stabilization aciton of any of the constitutents taken alone in a concentration equivalent to that used in the stabilizing combination. The described synergistic combination is achieved by the combination of the ortho-ester with 0.001 to 3% by weight and preferably 0.1 to 1% by weight of one or more of the compounds containing at least one of the following functions, groups or radicals, namely: aliphatic C -C alcohols, aliphatic C -C thiols, aliphatic C -C esters, aliphatic C -C nitriles such as C -C alkyl cyanides, aliphatic or cyclic ether-oxides such as C C epoxides, aliphatic C -C ketones, C C aliphatic or cyclic acetals, C -C aliphatic organic acid, aliphatic C C iminoether and ketimines, C -C nitroalkyls, oxygenated heterocycles such as pyrane, nitrogenous heterocycles such as pyrrolic, pyrrolinic; aliphatic C -C isocyanate, thiocyanate, isothiocyanate; C -C alkyl-orthocarbonates and C -C alkyl carbonates.

Among the halogen derivatives of saturated aliphatic hydrocarbons which are stabilized by the process of this invention are the following, which are given by way of illustration, but not by way of limitation, namely: dichloroethanes, trichloroethanes, 1,2-dichloropropane, 1,2 and 2,3-dichlorobutanes, tribromoethanes and 1,2- dibromopropane.

The following examples are given to illustrates the different aspects and the advantages of this invention and such examples should be taken by way of illustration but not by way of limitation.

EXAMPLES 1 TO 9 With the intent of showing the stabilizing effect of trimethylorthoformate (TMOF), on the one hand, and of trimethylorothoformate with 1,4- dioxane, nitromethane, trioxane, acetonitrile, tertiobutanol, respectively, on 1,1,1-trichloroethane, the following tests were carried out: the stabilizing agents, in the amounts set forth in the following table, were added to 40 ml. of 1,1,1-trichloroethane and heated to reflux in the presence of an aluminum plate having a thickness of 1 mm., a length of 7.5 mm. and a width of 12 mm. in which the aluminum was of 99.9% purity. The plate is partially immersed in the solvent. The refluxing was continued until the evolution of acid vapors and/or the development of a discoloration in the solvent and the time for the occurrence of one or the other of such events was recorded as representative of the stabilization ability of the stabilizing agent or stabilizing combination.

The following table summarizes the results obtained. By way of comparison and for better illustration of the merits of the invention, the same tests were performed with the same solvent under the same conditions with the following materials substituted for the stabilizing agent, namely: nitromethane, tertiobutanol, 1,4-dioxane, trioxane and acetonitrile. The foregoing compounds correspond to the compounds employed in the combination with trimethylorthoformate in Examples 1 to 9. A reference blank consisting solely of 1,1,1-trichloroethane without stabilizer was also included in the test.

Content of Grams of sta- Time preced- Stabdrzer stabilizer 1 bilizcr 2 ing 3 Example:

1 Trimethylorthoforg {EF mate (TMOF). 2 48 hr 50 Two 50 1. 5 100 hr. 1 50 4 5% 2 100 hi.

i 50 %Zg 1 100 hr. 1 50 fi g F 1. 5 100 111.

l i 50 T01 tiobutanol 50} 1 5 81 In TMO F 50 Aeetonitrile. 25 1 100 hr. Tertiobutanol. 25 8 Trimethylortho- 4 100 hr.

ac a 9 TMOF 70 Methanol 2O 3 100 hr Methylformate 10 Reference blank 0 3 min. N itromethane 0. 5 28 min.

1 40 hr. Tertiobutanol 0. 5 4 hr.

1 48 hr. 1,4-(iimr'mP 0. 5 3 hi.

1 20 hr. Acetonitrile 0. 5 38 min 1 50 hr. Trim'aus- 0. 5 min 1 1 hr. Methyliormate 2 30 hr. Methanol 2 hr.

Do O. (i min. Methyliormate 0. 3 5-1o min Methanol methylforniate 0. 6+0. 3 3-3 11. 30

1 Or of stabilizing composition percent by weight 2 Or of stabilizing composition per 100 gram 1,1,l-triehlorocthane. 3 The appearance of acid vapors or of a discoloration.

EXAMPLES 10 AND 11 Stabilization tests of 1,1-dichloroethane according to Examples 1 to 9 have been carried out and the obtained results have been indicated in the following table:

Per 100 grams 1,1-dichloroethane.

The appearance of acid vapors or of a discoloration.

It will be apparent from the results tabulated in the foregoing tables that the stabilization effect of the compound at 2 grams per 100 grams of solvent is almost twice as great as the compounds used as additives and tested alone and it will be apparent that the combination of stabilizers, representing the preferred practice of this invention, gives a stabilizing effect at 1.5 grams and 2 grams per 100 grams of solvent which is much greater than the stabilizing effect of any of the compounds alone when used in the same concentrations.

It will be apparent from the foregoing that there is provided a new and improved system for the stabilization of halogenated hydrocarbon solvents which is effective at low concentrations to maintain the stability of the hydrocarbon, even in the presence of metals.

It will be understood that changes may be made in the details of the formulations and combinations without departing from the spirit of the invention, especially as defined in the following claims.

We claim:

1. A composition formulated of a chlorinated or brominated alkane containing 2-4 carbon atoms selected from the group consisting of dichloroethanes, trichloroethanes, 1,2-dichloropropane, 1,2-dichlorobutane, 2,3-dichlorobutane, tribromoethanes, and 1,2-dibromopropane and a stabilizing composition comprising 0.001 to 15% by weight of trimethyl orthoformate and 0.001 to 3% by weight of at least one compound selected from the group consisting of C -C alkanols, C C alkyl cyanides, 1,4- dioxane, trioxane, and C -C nitro alkanes.

2. A composition formulated of 0.001 to 15% by Weight of trimethylorthoformate as claimed in claim 1 and 0.001 to 3% by weight of an alkanol having from 1-4 carbon atoms.

3. A composition formulated of 0.001 to 15% by Weight of trimethylorthoformate as claimed in claim 1 and 0.001 to 3% by weight of a C to C alkyl cyanide.

4. A composition formulated of 0.001 to 15% by weight of trimethylorthoformate as claimed in claim 1 and 0.001 to 3% by weight of a compound selected from the group consisting of 1,4-dioxane and trioxane.

5. A composition formulated of 0.001 to 15% by weight of trimethylorthoformate as claimed in claim 1 and 0.001 to 3% by weight of a C to C nitroalkane.

References Cited UNITED STATES PATENTS 2,947,792 8/1960 Skeeters 260-6525 3,265,747 8/1966 Cormany et a1. 260652.5 2,371,647 3/1945 Petering 260652.5 3,060,125 10/1962 Sims 260-6525 HOWARD T. MARS, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 564,061 Dated February 16, 197

Yves Correia et al.

It is certified that error appears --in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, at the top of the column headed "Grams of Stabilizer", the 0 immediately below 0.5 should be the numeral 1.

Signed and sealed this 15th day of June 1971.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. vJILLL WI E. SCHUYLER, JR. Attesting Officer Corrmissioner of Patents 

